1. Field of the Invention
The present invention relates in general to predistortion linearized amplifier systems and related methods. More particularly, the invention is directed to adaptive predistortion systems and methods.
2. Description of the Prior Art and Related Background Information
A digital transmitter, such as those employed in cellular telephones, has a digital baseband stage, a modulator, and a power amplifier. In order for a transmitter to be powered by batteries, the power amplifier must be efficient. Unfortunately, efficient power amplifiers often exhibit undesirable nonlinear gain. Linearization methods such as digital predistortion can improve the overall system performance of digital transmitters, but these systems require calibration in order to ensure optimum system performance.
Accordingly, a need exists to improve the calibration of digital predistortion systems.